1. Field of the Invention
The present invention relates to expansion card mounting structures for computers, and more particularly to an expansion card mounting structure which can provide ground connection to attenuate electromagnetic interference (EMI).
2. Description of Related Art
Most computers are designed to have replaceable or expandable equipment and components. Generally, expansion cards or interface cards are the hardware used to allow expansion of functions of personal computers. Consequently, a typical personal computer enclosure is configured to have a number of expansion slots that allow users to install optional expansion cards. However, the number of expansion slots provided proportionately increases the amount of EMI that is emitted from the computer.
Nowadays, most manufacturers recognize the need to improve ground connections and control EMI. A variety of apparatuses have been developed for expansion card mounting structures to attenuate EMI.
U.S. Pat. No. 5,650,922 by Ho discloses an expansion card mounting structure which provides ground connection for expansion cards. The mounting structure comprises a card mounting seat and a ground plate. The mounting seat is provided with a plurality of first slots. Both lateral sides of each first slot are respectively provided with retaining holes. The ground plate has a shape substantially identical to that of the card mounting seat. The ground plate defines a plurality of second slots for matching with the first slots of the card mounting seat. The lateral sides of each second slot are respectively provided with hooking means for matching with the retaining holes of the card mounting seat. Each second slot also has a plurality of projecting contact pieces at rims of the lateral sides thereof.
In use of the card mounting structure of Ho, the ground plate is fitted into the card mounting seat such that the hooking means of the ground plate engage in the retaining holes of the card mounting seat. The expansion card is inserted into the card mounting seat. The projecting contact pieces at both sides of each second slot tightly contact the expansion card, achieving good ground connection between the expansion card and the card mounting seat.
However, the complex structure of the grounding plate complicates manufacturing of the card mounting structure. Assembly of the grounding plate to the card mounting seat is also unduly complicated. These features increase manufacturing costs. Additionally, computers may accommodate varying numbers of expansion cards. If the number of the expansion cards is changed, then frequently a new grounding plate is also needed. One grounding plate cannot necessarily be universally installed in a variety of different computers. For mass producers, when a new grounding plate is needed, then usually a new die for forming the new grounding plate must be made. This also results in increased costs.
Accordingly, an object of the present invention is to provide an expansion card mounting structure which provides ground connection to attenuate electromagnetic interference (EMI).
Another object of the present invention is to provide an expansion card mounting structure which is simple.
A further object of the present invention is provide an expansion card mounting structure which is cost-efficient.
In order to achieve the objects set out above, an expansion card mounting structure comprises a card mounting seat and a plurality of covers to mount expansion cards thereon. The card mounting seat defines a plurality of expansion slots therein. A plurality of spaced projecting contact fingers is integrally formed on the card mounting seat along longitudinal extremities of the expansion slots. In assembly, the covers are secured to the card mounting seat and cover the expansion slots. The contact fingers deflectably contact the covers, to establish good ground connection and thereby attenuate EMI.